Pregnant women should probably add cellphones to the list of things they need to avoid, along with alcohol, sushi and cat poo. A giant study that surveyed over 13,000 children found that women who used mobile phones when pregnant were more likely to give birth to kids with behavioral problems.

The study, conducted by UCLA and Aarhus University in Denmark, found that using cell phones just two or three times a day would raise the risk of their babies developing hyperactivity and emotional disorders by the time they enter Kindergarten.

The scientists responsible for the study say that the results were "unexpected," and that they haven't discovered what biological mechanisms causes the problems. But the results stayed the same even when they accounted for other possible causes—such as smoking, family psychiatric history or socio-economic status.

But before everyone freaks out and buys a MummyWrap, the scientists stress that the results "should be interpreted with caution" and affirmed by other studies. In the meantime, maybe tell Mommy-to-be to limit her cellphone use a little bit, just in case. [The Independent via Textually]